An example of a known type of next-generation network is the IP (Internet Protocol) Multimedia Subsystem (IMS), a next-generation core network architecture for mobile and fixed services, defined by the 3rd Generation Partnership Project (3GPP). See, for example, the 3GPP Technical Specification (TS) documents, including 22.228, 22.250, 22.340, 22.800, 23.218, and 23.228, which are incorporated by reference herein. An IMS network utilizes Session Initiation Protocol (SIP) as a signaling protocol for establishing, modifying and terminating multimedia sessions between users in the network. SIP is described in, for example, J. Rosenberg et al., “SIP: Session Initiation Protocol,” Internet Engineering Task Force (IETF) RFC 3261, June 2002, which is incorporated by reference herein.
A network element that processes and forwards SIP messages is called a proxy server in SIP terminology, and a Call Session Control Function (CSCF) in IMS terminology. 3GPP defines three types of CSCF elements: Proxy CSCF (P-CSCF) which is the interface to the user, Interrogating CSCF (I-CSCF) which provides an interface to other servers in different administration domains, and Serving CSCF (S-CSCF) which handles registration, enforces policy and provides an interface to application servers.
In designing any network, it is important to create a topology that will satisfy the demands of the network operator. One key step in creating a topology involves assigning user nodes to specific network nodes so as to provide the users with required functions. A user node may be, for example, a point of interconnection where traffic from several users is aggregated. A network node may be, for example, an entity in the network that provides a particular network function required by a user. The process of assigning user nodes to network nodes is generally referred to herein as “homing.”
A problem that arises in conventional network design techniques is that certain features of next-generation architectures such as IMS can complicate the process of homing user nodes to network nodes. For example, the IMS architecture generally separates transport, media, session and application functions into different layers, which makes it much more difficult to determine an appropriate homing of the user nodes to the network nodes than in a network which does not exhibit such separation of functionality. Nonetheless, there is no suitable automated procedure available for performing the homing process in IMS networks and other next-generation networks. Instead, this homing process is often implemented manually, and is therefore extremely time consuming and prone to error.
Accordingly, a need exists for an improved approach to homing of user nodes to network nodes in IMS networks and other types of communication systems.